This 4-year competing continuation will extend the follow-up for 750 subjects enrolled in a randomized interventions trial, Project STYLE: "HIV Prevention for Youth with Severe Mental Illness" (R01, MH 63008). Extending the follow-up from one year to 36 months will 1) discern the long-term impact of the Project STYLE interventions and 2) permit complex modeling of the predictors and trajectories of sexual health (delay of sex) and risk (incident STIs). Adolescents, particularly those in mental health treatment, are at risk for HIV because of sexual and substance behaviors. Parent-child communication about sexual topics and parental supervision are associated with delays in the onset of sexual activity and more responsible sexual behavior;thus, the parent project, Project STYLE, is a randomized trial that is evaluating the comparative efficacy of three interventions: a) family-based HIV prevention intervention, b) adolescent-only HIV prevention intervention, and c) general health promotion intervention. This multi-site project (Rhode Island Hospital, Emory University, and the University of Illinois at Chicago) is enrolling an ethnically/racially/geographically diverse group of 750 adolescents in outpatient mental health treatment and their parents. Subjects receive a full day group intervention on the day of randomization, return in two weeks for an individual session, participate in a half day booster session three months later, and are assessed six and 12 months after the intervention. This application offers a unique opportunity to assess this already ascertained sample at three additional points (24,30, and 36 months). This is important because few studies have examined the longer-term predictors of the delay of sex and incident STIs over 36 months using a comprehensive array of family functioning, family monitoring/communication, and trauma history. Additionally, this continuation will provide important data concerning the long-term impact of Project STYLE'S theoretically based HIV prevention programs which are designed to maintain safe sexual behaviors. The Family-Based program has increased parent/adolescent sexual communication and reduced adolescent unprotected sex after six months and extended assessment will determine whether these benefits are maintained over time. Public Health Significance: (1) Examination of the long-term impact of HIV prevention programs will guide the development of programs that are highly effective at maintaining safe adolescent behavior. (2) Understanding factors related to delay of sex and STI incidence especially among vulnerable youth with high rates of psychiatric comorbidities is important in reducing HIV infections.